Process for preparation of cross-linked epichlorohydrin polymer

ABSTRACT

A PROCESS FOR THE PREPARATION OF AN EPICHLOROHYDRIN POLYMER HAVING IMPROVED PROPERTIES, WHICH COMPRISES TREATING A BLEND CONSISTING OF 100 PARTS OF AN EPICHLOROHYDRIN POLYMER HAVING A MOONEY VISCOSITY ML1+4 (100* C.) OF 30 TO 140 AND 1-30 PARTS BY WEIGHT OF A DIENE/ ACRYLONITRILE COPOLYMER SELECTED FROM A BUTADIENE/ACRYLONITRILE COPOLYMR AND AN ISOPRENE/ACRYLONITRILE COPOLYMER WHICH HAS A BONDED NITRILE CONTENT OF 10 TO 60% BY WEIGHT AND A MONEY VISCOSITY ML1+4 (100*C.) OF 30 TO 130, WITH A CROSS-LINKING AGENT WHICH CROSSLINKS THE EPICHLOROHYDRIN POLYMER BUT NOT THE DIENE-ACYLONITRILE COPOLYMER.

April 18, 1972 KE|J| KQMURQ EIAL 3,657,393

PROCESS FOR PREPARATION OF CROSS-LINKED EPICHLOROHYDRIN POLYMER Filed Jan. 21, 1970 2 Sheets-Sheet 1 TIME (MINUTE) TORQUE (kg cm) TIME (MINUTE) A T-M m, 1972 PROCESS ma PREPARATION OF CROSS-LINKED EPICHLOROHYDRIN POLYMER Filed Jan. 21, 1970 HAR DNESS KEIJ] KOMURO Er AL 3,657,393)

2 Sheets-Sheet z W To- 0 6O 0 CONTROL EXAMPLE 5 (HARDNESS OF SPECIMEN 79) TEsT EXAMPLE 26 (HARDNESS OF SPECIMEN 72) 50 O -s F I I K 50 I00 500 |o0o AGING TIME TEsT TUBE METHOD United States Patent Olfice 3,fi57,393 Patented Apr. 18, 1972 Int. Cl. (16st 29/12 US. Cl. 260-887 3 Claims ABSTRACT OF THE DISCLOSURE A process for the preparation of an epichlorohydrin polymer having improved properties, which comprises treating a blend consisting of 100 parts of an epichlorohydrin polymer having a Mooney viscosity ML (100 C.) of 30 to 140 and 1-30 parts by weight of a diene/ acrylonitrile copolymer selected from a butadiene/acrylonitrile copolymer and an isoprene/acrylonitrile copolymer which has a bonded nitrile content of to 60% by weight and a Mooney viscosity ML (100 C.) of 30 to 130, with a cross-linking agent which crosslinks the epichlorohydrin polymer but not the diene-acrylonitrile copolymer.

This invention relates to a process for the preparation of a cross-linked epichlorohydrin polymer having improved properties which is selected from the group consisting of an epichlorohydrin homopolymer and copolymers of epichlorohydrin with alkylene oxides.

More particularly, the invention relates to a method of producing an epichlorohydrin polymer having improved properties which comprises treating a blend of an epichlorohydrin homopolymer and/or a copolymer of epichlorohydrin and an alkylene oxide (hereinafter generically called an epichlorohydrin polymer) and a butadiene/acrylonitrile copolymer or an isoprene/acrylonitrile copolymer (hereinafter generically called a diene-acr ylonitrile copolymer) with a cross-linking agent which crosslinks the epichlorohydrin polymer but not the dieneacrylonitrile polymer.

The epichlorohydrin polymer is an elastomer having an ether bond in its main chain which is obtained by the ringopening polymerization of an epoxy group, and has excellent characteristics in resistance to oil, heat, cold, weather, chemicals and gas-impermeability. At present, in automobiles, airplanes, refrigerators and in the fields of machine parts, nitrile rubber and chloroprene rubber are used as oil-resistant hoses, gaskets, O-rings and oil seals, but are found not entirely satisfactory. Since the epichlorohydrin polymer has the above-mentioned excellent characteristics, they are expected to be fully utilizable in these applications. However, the epichlorohydrin polymer has some defects, for instance, in processability, a sagging phenomenon during vulcanization, strength characteristics, deterioration with softening, and wear resistance. Owing to an inherent stickiness, the epichlorohydrin polymer has poor processability in ordinary roll kneading, and exhibits a sagging phenomenon (hot flow) in the cross-linking of such a product as hose, resulting in the non-uniformity of cross-linked products. The cross-linked epichlorohydrin polymer is inferior in break strength and wear resistance, too. Furthermore, since the epichlorohydrin polymer has no unsaturated bond in its main chain, it is essentially excellent in resistance to oxidation and heat but owing to deterioration with softening, the product is deformed when it is used as an oil seal and O-ring, resulting in a decrease of commercial value. This leads to a demand for improvement towards deterioration with hardening.

Heretofore, the characteristics of rubber have been improved by blending compounding agents or mixing with other rubber having excellent properties and covulcanizing the mixture. Blending a compounding agent such as carbon is not particularly effective in removing the defects of an epichlorohydrin polymer. Mixing and covulcanization with other rubbers are technically difficult, and many problems have been left unsolved because different crosslinking agents and cross-linking promotors are necessary. It is well known that the epichlorohydrin polymer differs from the diene-acrylonitrile polymer in cross-linking system and speed; the former exhibits a slow speed of crosslinking while the latter, a rapid speed of cross-linking. No cross-linking system for the epichlorohydrin polymer has been found which shows a rapid cross-linking speed. When these two polymers are covulcanized, vulcanization becomes excessive since the phase of the diene/acrylonitrile polymer is vulcanized at a speed faster than a phase of the epichlorohydrin polymer, resulting in an abnormal rise in modulus and lowering in elongation. This not only irnpairs the initial vulcanization properties, but also changes the physical properties drastically after heat aging.

An object of the invention is to provide a rubber vulcanizate in which the defects of the epichlorohydrin polymer have been eliminated, namely, a rubber vulcanizate having improved sagging phenomenon, strength characteristics, aging properties and wear resistance.

It has now been found that this object of the invention can be achieved simply by blending a diene-nitrile polymer with an epichlorohydrin polymer as an organic filler unlike the conventional covulcanization. An improved cross-linked epichlorohylrin polymer can be obtained by blending an epichlorohydrin polymer (an epichlorohydrin homopolymer and/ or copolymers of epichlorohydrin with alkylene oxides) with 1-30 parts by weight, preferably 5- 10 parts by weight of a diene/acrylonitrile copolymer (a butadiene/acrylonitrile copolymer and/ or isoprene/ acrylonitrile copolymer) per parts by weight of the epichlorohydrin polymer, and cross-linking the blend with a known cross-linking agent usually used in the cross-linking of an epichlorohydrin polymer. It has been said that suitable properties cannot be attained unless a suitable vulcanization is effected. The same can be said with respect to covulcanization. If two rubbers which can be vulcanized by the same vulcanizing system are compounded and vulcanized, a suitable degree of vulcanization can be obtained by adjusting the vulcanization temperature and time. But if each of the two rubbers is vulcanized by a different vulcanizing system, the use of a vulcanizing system for only one of the two rubbers leaves the other rubber completely unvulcanized, and it has been thought that this does not raise the vulcanization degree of the mixed vulcanizate and impairs the initial properties. The present invention has a great feature in that in crosslinking a blend of the epichlorohydrin polymer and the diene-acrylonitrile polymer, the defects of the epichlorohydrin polymer can be eliminated by using a cross-linking agent which does not cross-link. the diene/acrylonitrile polymer.

In the accompanying drawings, FIG. 1 is a graphic representation showing the cross-linking state of the epichlorhydrin polymer in Example 2; FIG. 2 is a graphic representation showing the cross-linking state of the butadiene/ acrylonitrile polymer in Example 2; FIG. 3 is a graphic representation showing the effect of improvement of softening deterioration in Test Example 26 in Example 6.

The blend of the epichlorohydrin polymer and the diene-acrylonitrile copolymer in the present invention has a very excellent roll kneadability, and a rubber vulcanizate obtained by cross-linking the blend with a cross-linking agent usually used in the cross-linking of the epichlorohydrin polymer exhibits a very improved sagging phenomenon. Small amounts of a butadiene/acrylonitrile copolymer modified with divinyl benzene or divinyl pyridine or a diene/acrylonitrile copolymer obtained by polymerization at high temperatures and having a very high Mooney viscosity ML 100 C.) effectively bring about the improvement of a sagging phenomenon. Furthermore, the rubber vulcanizates otained in accordance with the present invention have improved strength characteristics, showing low hardness, high elongation and high break strength at room temperature, and also have improved wear resistance. Furthermore, as shown in FIG. 3, a softening deterioration phenomenon is prevented. It is surprising that in a long period heat aging test, the vulcanizate of the present invention remains hard and is not softened. If, however, the amount of the diene/acrylontrile copolymer rubber exceeds 30% by weight, the strength characteristics and oil resistance of the blend are inferior.

The epichlorohydrin polymer used in the blend includes an epichlorohydrin homopolymer, copolymers of epichlorohydrin with alkylene oxides, e.g., an epichlorohydrin/ ethylene oxide copolymer, an eichlorohydrin/ propylene oxide copolymer, an epichlorohydrin/ethylene oxide/propylene oxide copolymer, and an epichlorohydrin/allyl glycidyl ether copolymer, and mixtures of these, and should have a Mooney viscosity ML (100 C.) of 30 to 40. The diene/aciylonitrile copolymer is obtained by customary emulsion-polymerization or solution-polymerization, and has a bonded nitrile content of -60% by Weight and a Money viscosity ML (100 C.) of 30 to 130. When it is a butadiene/acrylonitrile copolymer rubber, it may be modified with divinyl benzene or divinyl pyridine.

As the cross-linking agents suitale for the cross-linking of the epichlorohydrin polymer, aliphatic polyamines such as ethylene diamine, hexamethylene diamine and triethylene tetramine, aromatic polyamines such as paraphenylene diamine, metaphenylene diamine and cumenediamine, polyamine carbamates such as ethylene diamine carbamate and hexamethylene carbamate, ketopolyamines such as urea, biuret, thiourea and dibutyl thiourea, and combinations of such compounds, Z-mercapto imidazolines or Z-mercapto pyrimidines with a compound of a metal of Group II-A, II-B, IIIA, IVA or VA of the periodic table are known. The most preferable combination to be used in the present invention is a combination of Z-mercaptoimidazoline and lead tetratrioxide.

The rubber cross-linked product according to the present invention is obtained by mixing the epichlorohydrin polymer and the diene-acrylonitrile copolymer with a mixer such as a roll mill and Banbury mixer, or mixing them in a solution and thereafter drying the mixture followed by cross-inking. The effects of the present invention are not impaired even if such usually used compounding agents as reinforcing agents, fillers, softening plasticizers and antioxidants are compounded with the mixture.

The invention will be described specifically by the following examples in which all parts are by weight.

EXAMPLE 1 Blends were prepared in accordance with the compounding recipe given in Table 1, and the roll kneadability of each blend was examined using an 8-inch roll at a temperature of 50 to 60 C. rolling at 2024 r.p.m. The epichlorohydrin homopolymer had Mooney viscosity ML (100 C.) of 55. The butadiene/acrylonitrile copolymer and isopreneacrylonitrile copolymer had Mooney viscosities ML (100 C.) of 100 and 70, respectively. The results are shown in Table 1. For the sake of comparison, the results obtained with the epichlorohydrin homopolymer alone are also shown in Table 1.

It is seen from this example that by blending 10 parts by weight of the butadiene/acrylonitrile copolymer or isoprene/acrylonitrile copolymer with the epichlorohydrin homopolymer, the processability of the obtained blend is remarkably enhanced.

EXAMPLE 2 Blends were prepared in accordance with the compounding recipe shown in Table 2. Each blend was crosslinked with an oscillating disk rheometer at 155 C, and its torque was measured. As is seen from FIG. 1 (the torque of the epichlorohydrin homopolymer) and FIG. 2 (the torque of the butadiene/acrylonitrile polymer), the cross-linking of the butadiene/acrylonitrile copolymer does not take place in a crosslinking system used in the crosslinking of the epichlorohydrin homopolymer, In Test Example 5, the isopi'ene-acrylonitrile copolymer produced the same results as with the butadiene/acrylonitrile copolymer.

TABLE 2 Test Ex. (parts) Eplchlorohydriii homopolymer, 100 Hycar 1041 1 100 Krynac 833 100 Tin stearate 1 1 1 Trilead tetroxlde. 5 5 5 FEF grade carbon 50 50 50 Z-mercaptoimldazollne 1. 5 1. 5 1.5 Nickel dlbutyldithlocarbaruate 2.0 2.0 2.0

1 See footnote bottom of Table 1.

2 Tradename of a butadiene/aci'ylonitrile copolymer (product of Goodn'ch Chemical, U.S.A.; having a Mooney viscosity MLm (100 C.) of

3 See footnote bottom of Table 1.

EXAMPLE 3 Rod-like blends were prepared in accordance with the compounding recipe shown in Table 3. Each blend having a length of 15 cm. was fixed horizontally at both ends at 150 C. in a gear-type air heating ageing tester, and cross-linked for 18 hours. The results obtained are shown in Table 3. The extent of sagging given in the table shows the maximum distance over which the horizontally fixed specimen was sagged during crosslinking. It is seen from the results obtained that a sagging phenomenon (during vulcanization) can be remarkably improved by blending the butadiene/acrylonitrile copolymer or isoprene/acrylonitrile copolymer.

TABLE 3 Control Test Ex. (parts) Ex. 2 *v (parts) 6 7 8 9 10 Eplchlorohydrin homo- 100 100 100 100 100 polymer 1 Hycar 1411 2 10 30 Hycar 1042 x 82 10 30 Krynae 833 4 10 Tin stearate 1 1 1 1 1 1 Trilead tetroxide 5 5 5 5 5 5 FEF grade carbon 50 50 50 50 50 50 2-mcrcaptoimidazollne 1. 5 1. 5 1. 5 1. 5 .15 1.5 Nickel-dibiityldithio- 2.0 2.0 2.0 2.0 .2. 0 2.0

carbamate. Extent of sagging, cm 4. 5 3.0 2.0 3. 5 3.0 3.0

cross-linked gel).

4 See footnote bottom of Table 1.

EXAMPLE 4 Blends were prepared in accordance with the compounding recipe shown in Table 4. Each blend was kneaded with two roll mills at 50 to 80 C., and cross- 6 EXAMPLE 5 The strength characteristics and wear resistance were examined in the same manner as in Example 4 except using an epichlorohydrin/ethylene oxide copolymer (Hylinked in a steel mold for 30 minutes at 155 C. The 5 d-rin 200, ML (100 C.)=95, Goodrich Chemical,

strength characteristics and wear resistance of the blend were examined. The results are shown in Table 5. It is seen from the results obtained that the tensile strength, elongation and wear resistance of the blend are improved U.S.A.) instead of the epichlorohydrin homopolymer used in Example 4. The results are shown in Table 6. Improvements are seen in the tensile strength, elongation and wear resistance like Example 4.

TABLE 6 Test Ex. Control Blended butadiene-acrylouitrile copolymer, Hycar 1000 x 132 1041 1411 1042 1042 x 82 1043 1014 Tensile strength (kg./cm 145 158 177 173 169 161 159 164 Elongation (percent). 230 310 370 350 400 340 410 420 10 3 129 131 108 113 107 105 81-79 79-76 79-76 78-75 78-76 78-75 77-75 76-74 1200 950 1000 650 8 0 850 800 by compounding 10 parts of the butadiene/acrylonitrile copolymer. EXAMPLE 6 An epichlorohydrin homopolymer having a Mooney TABLE4 viscosity ML (100 C.) of was compounded with E E s a butadiene/acrylonitrile copolyrner having an ML ri d 0 (100 C.) of or an isoprene/acrylonitrile copolymer having an ML 4 C.) of 70 at 50-80 C. by means 1 00 00 3t3ii%i',- fi$fi, 8$ner 10 of two roll mllls 1n accordance with the recipe shown in 11 1 st a ge g Ta'ble 7, and the blend was cross-linked for 30 minutes at 2-;116363, to fi bifii 155 C. in a steel mold. The strength characteristics, wear gggfi ig g g 8 resistance, resistance to aging and oil resistance were gm at 0 examined. The aging test was conducted in a test tube See foot ot bottom of Table type air heating aging tester at 150 C. The results are TABLE 5 Test Ex.- Control Bl d dbutadiene-acr lonitrile :J pJlymeLH can"? 1000 x 132 1 1041 8 1411 4 1042 6 1042 x 82 B 1043 1 1014 Tensile strength (kg [cm 2 158 161 183 169 173 177 185 179 Elongation (percent) 280 350 380 300 340 330 350 320 200% modulus (kgJcmJ). 147 124 124 134 129 131 Hardness (JI 82-80 76-71 72-68 78-74 70-66 74-70 72-68 74-71 Williams Wear (cc/H hr.) 900 650 770 800 730 690 720 660 1 Butadiene-acrylonitrile copolyrner (amount of nitrile: 50%;M0oney viscosity; M11114 (100 0.) =48, a product of Goodrich Chemical, U.S.A.)

2 Butadiene-acrylonitrile cgpflymer (amount of nltrile: 40%, Mooney viscosity; MLiH (100 C.) =85, a product of Goodrich Chemical, U.S

8 Butadieneacrylonitrile copolymer (amount of nitri le: 40%, Mooney viscosity; MLH-l (100 C.) 100, a product of Goodrich Chemical, U.S A.)

4 13utadiene-acrylonitrileS cxpflymer (amount of nitrile: 34%, Mooney viscosity; ML (100 C.) =84, a product of Goodrich Chemical U 5 Butadiene-acrylonitrile copolymer (amount of nitrile: 34%, Mooney viscosity; MLM (100 CQ)=83, a product of Goodrich Chemical, U.S A

B Butadiene-acrylonitrile copolymer mmount of nitrile: 28%, Mooney viscosity; ML1+4 (100 0.) =82, a product of Goodrich Chemical, U.S A

Butadiene-acrylonitrile c opo lymer (amount of nltrile: 18%, Mooney viscosity; ML; (100 C.)=73, a product of Goodrich Chemical, U.S.AJ.

shown in Table 8. Control Example 6 was practiced in accordance with the conventional covulcanization recipe.

TABLE 7 Control Test Ex. parts Control Ex. 5 Ex. 6 (parts) 25 26 27 28 (parts) Epichlorohydrin homopolymer 1 100 100 100 100 100 100 Hycar 1041 B 6 30 30 Krynac 833 10 Tin stearate---- 1 2 1 1 1 1 Trilead tetroxide 5 5 5 5 5 5 Zinc flower 1. 5 FEF grade carbon- 50 2-mercaptomidazoline 1. 6 Drbenzothiazyl disulfi 0. 6 Sulfur 0. 45 N ickel-dibutydithlocarbama 2. 0

1 See footnote bottom of Table 1. 1 See footnote bottom of Table 5. 3 See footnote bottom of Table 1.

TABLE 8 Test Ex.- Control Control Ex. 26 27 Ex. 6

Tensile strength (kg/em?) 153 173 179 189 175 177 Elongation (percent) 290 330 370 510 350 240 100% modulus (kg/cm 77 69 61 38 66 99 200% modulus (kg/em. 143 136 130 90 132 152 Hardness (J IS) 79-75 75-73 72-69 66-61 77-74 7169 Block cross-linked for minutes:

Repulsive elasticity (percent) 18.0 19. 5 20. 5 25.0 18. 5 26. 5 Permanent strain on compression (percent) 130 0. x 70 hours 67.4 07.0 65.3 67.8 0&5 67.1 Williams wear (ecJiP hr.) Dipped of 100 C. for 70 hours in ASTM #3 oil:

Tensile strength (kg/cm!) Elongation (percent) 200% modulus (kg./em. Hardness (JIS) Change in volume (percent) Immersed for 70 hours at room temperature in fuel B:

Tensile strength (kg/cm!) Elongation (percent) 200% modulus (kg./cm. Hardness (J IS) Change in volume (percent) After aging for 3 days at 150 0.:

Tensile strength (kg./em. 180 177 170 150 Elongation (percent) 130 130 130 150 100% 1110111111115 (kg/cm?) 1 91 (J1 Alter aging (or 20 days at 150 Elongation (percent) 220 (3 100% modulus (kg/cm!) 17 Hardness (J IS) 70-60 88-85 91-90 1 Not measurable owing to hardening.

The oil resistance was not deteriorated even when the butadiene/acrylonitrile copolymer was compounded. After 45 aging for 20 days, the crosslinked epichlorohydrin homopolymer was softened, but the blend remained hard (FIG. TABLE 10 3). Furthermore, as shown in Control Example 6, accord- Test ing to the conventional covulcaniztion method, the modu- Control lus of the resulting blend was very high, showing 99 for EL? 28 29 100% modulus and 152 for 200% modulus. It is seen Tensilgstfength (kg/cm!) 145 177 174 Elongation (percent) 230 370 540 from the data obtained after a 8171 day ageing that a 100% modulus (kg mm L 76 67 45 hardening deterioration occurs too abruptly. 200% m l (kg 1 109 129 030 Hardness (JI 81-79 79-76 74-09 EXAMPLE 7 Williams Wear (cc/H hr.). 1,200 1,000 800 After aging for 3 days at 150 C.. An epichlorohydrin/ ethylene oxide copolymer rubber g nsne trerzgth G g 011 9. 011 010011 having an ML (100? C.) of 95 was compounded with loo%gmoduh?s mg lama" 129 134 158 a butadiene/acrylomtnle copolymer rubber having an Aftelrlarcllnesfs (gI) 1.5 0 C. 84-82 84-81 81-78 n l 8 S 3 ML (100 C.) of 85 m accordance with the reclpe gg g i fi' (kg/cm 63 (1) shown in Table 9, and the resulting blend was sub ected g ga g fo fi 2g to an aging test under the same conditions as in Example 313 Eff: 7H0 "@5155, 6. The results obtained are shown in Table 10.

1 N at measurable owing to hardening.

TABLE 9 Control Test Ex. parts Ex. 7, parts 28 29 Epichlorohydrlnlethylene oxide eopoly- EXAMPLE 8 me 1 100 100 100 g gg ggig g 7 0 An epichlorohydrin homopolymer having an ML Tmead gg ag 5 5 5 (100 C.) of 55 was compounded with a butadiene/ FEF grade carbon... 50 50 50 1 2 mercaptoinlidazoline u L 5 1.5 L 5 flcrylomtrlle copqlymer havlpg an l-l-Q C) of Nickel dibutyl ditmocarbamm Z0 Z0 0 in accordance wlth the recipes shown 1n Tables 11, 13

and 15, and the aging test was conducted under the same conditions as Example 6. The test results are shown in Tables 12, 14 and 16. A series of these experiments was conducted with the use of various cross-linking agents. TABLE 13 Test Ex.-

TABLE 11 Hydrin 100 100 100 Hycar 1041 0 Text Ex. Zinc stearate 1 1 Control Trilead tetroxid 6 5 Ex. 8 30 31 FEF grade earbo 30 30 1O Nickel dibutyl dlthio 1 1 gydrinla 100 11118 138 Trimethyl thiourea 2. 5 2. 5

year Zinc stearate l 1 1 I See footnote bottom Table 1 Trilead tetroxi 5 5 5 2 See footnote bottom Table 2. FEF grade carbon 30 30 30 Niekel-dibutyldithiocarbamate 1 1 1 Hexamethylene diamine .1 0. 75 0. 75 0.75

,. 1 See footnote bottom of Table 1. 3 See footnote bottom of Table 2.

TABLE 14 Test Ex.- TABLE 12 Control Text Ex. 32 33 g 31 Cross-linked for 30 minutes at 155 0.:

gfnsiletstrength (kgj/em. 17(11 193 onga on pereen 68 79 CIOSS-lllllid for 30 minutes at 155 C.. 100% modlflus (kg'lcmjLu 41 31 25 Tensile strength (kg/em. 152 167 180 200% modulus (kgJcmghn 69 62 53 fi}g.g ffggg gifgg fg 2 2: 5g Hardness (I IS) I 61-58 51-19 47-45 200% modulus (k I cmh) 89 E5 54 30 YfP5 6 Hardness (HS) 7674 7H8 Tensile strength (kgJemfi)... 19 25 32 Willi-Ems wear (cm/P1112 500 450 350 Elongation (percent) 320 180 150 After aging for 6 days at 150 C.: 100% modulus (kg /cm 10 21 28 Te s eng h e/ -L. 41 53 49 Hardness (J1 5M4 8H0 8H7 gg igz gfiiz g 5 gg 22 After aging for 20 days at 150 0.:

v ,2 i 1 Hardness 85-17 81-79 14-71 tfggggggif zggigg%, 2 E3 8 Aite i agin g for 20 at 150:)0. 15 0) 100% modulus h: (2)

ensi e s reng g. cm. fig$ fl2i tlf e gffnygfi 55 2 5 1 1 Hardness (J IS) 96-94 0 m0 1 Not measurable owing to hardening. Hardness (HS) 53-50 91*90 9492 I The specimens were broken owing to softening.

1 Not measurable.

TABLE 15 Control Test Control Test Control Test Ex. 10 Ex. 34 Ex. 11 Ex. 35 x. 12 Ex. 36

Hydrin 100 1 100 100 100 100 100 100 Hyear 1041 10 10 10 Zinc stearate 1 1 1 1 1 1 Dibasie lead phthalate- 5 5 Dibasie lead phosphite 5 5 Magnesium oxide 5 5 FE F exrbon 50 50 50 50 50 Nickel-dubutyl-dithioeerbamate. 2 2 2 2 2 2 2-mercapto-imidazoline 1. 5 1. 5 1. 5 1. 5 1. 5 1. 5

1 See footnote bottom Table 1. See footnote bottom Table 2.

TABLE 16 Control Test Control Test Control Test Ex. 10 Ex. 34: Ex. 11 Ex. 35 Ex. 12 Ex. 36

Gross-linked for 30 minutes at 155 0.:

Tensile strength (kg/0111. 125 142 138 153 135 155 51 257 3 22 23 2s 12 me u 11s em. Har dness (J IS) g 80-72 -65 -74 69- 64 74-70 61-57 After aging for 6 days at 150 0.:

Tensile strength (kg/em?) 113 107 98 138 118 Eloigatignfpezfienf) 3.- 212 13g 2Z8 90 238 80 10 mo u us g. cm. Hardness (I IS) 1 80-72 81-76 80-71 82-80 77-74 79-78 After aging for 20 days at C.

Tensile strength (kg/emf) 38 12 0) 54 (U glgigetign1(perf{en;:). 3 28(5) 380 22(1) mo u us em. Har lness (J IS) i 52-50 92-90 50-48 93-92 58-56 93-91 Not measurable owing to hardening.

What is claimed is:

1. A process for the preparation of an epichlorohydrin polymer having improved properties, which comprises treating a blend consisting of an epichlorohydrin polymer having a Mooney viscosity ML (100 C.) of 30 to 140 and 1-30 parts by weight per 100 parts by weight of said epichlorohydrin polymer of a diene/acrylonitrile copolymer selected from a butadiene/acrylonitrile copolymer and an isoprene/acrylonitrile copolymer having a bonded nitrile content of 10 to 60% by weight and a Mooney viscosity ML (100 C.) of 30 to 130, with a cross-linking agent selected from the group consisting of aliphatic polyamines, aromatic polyamines, polyamine carbamates, ketopolyamines, 2-mercapto imidazolines with a compound of a metal, and Z-mercapto pyrimidines with a compound of a metal which cross-links said epichlorohydrin polymer in the absence of a cross-linking agent which cross-links said diene/acrylonitrile copolymer.

12 2. A process of claim 1 wherein said epichlorohydrin polymer is an epichlorohydrin homopolymer.

3. A process of claim 1 wherein said epichlorohydrin polymer is a copolymer of epichlorohydrin with an alkyl- 5 ene oxide.

References Cited UNITED STATES PATENTS 3,351,517 11/1967 Willis 161-184 3,445,544 5/1969 Schmitt 260-876 SAMUEL H. BLECH, Primary Examiner C. J. 'SECCURO, Assistant Examiner U.S. Cl. X.R. 

